The number one innovation that has made off-grid life more than just tolerable is low-voltage LED lighting. It's wonderful to be able to work in a well-lit space without worrying so much about battery life. All lighting is on mechanical timer switches, walking out of a room and leaving the lights on is a bad habit that's hard to break.
The next innovation to increase utility and practicality will likely be LFE (LiFePO4) batteries. In 30 years I have worn out or accidentally destroyed dozens of lead-acid batteries in various forms. They are fragile and heavy. Moving them by boat is brutal. I have high hopes that my current set of replacements will be the last ones for many years.
Electrical loads keep increasing. First lights, then radios and phones. Now laptops and a long-range WiFI link for remote work, and overnight power for CPAP machines. Next up will be DC solar powered refrigeration to displace propane. That will require more panels, more batteries but will have an immediate and long lasting benefit.
It has been a long and mostly satisfying project which has benefitted everyone around me.
The batteries are the weakest link, but now we have LTO batteries (20k cycles), and Sodium ion starting to be available.
So far the one LFP battery I have deployed has been operating properly but there were some initial compatibility issues - my solar regulator did not interact well with the BMS despite alleged compatibility. That cost me several hundred dollars in downstream equipment damage due to voltage surge.
I am watching the new solid-state lithium batteries with great interest.
In particular I like the ‘do you really need a battery’ part. My system is over-spec (partly because small solar panels aren’t really worth buying any more) but the battery is really overkill for the lighting setup it currently powers.
The nudge to think about using a convertor plus Lithium-Iron power banks would have probably made me think about switching to that approach until I needed higher amounts of storage.
I originally heard about a company called SunRay doing it but I’ve seen seen them on Amazon and heard of a bunch of other ones.
There are also a bunch of DC air con units and heat pumps.
We live in good times for off grid and hybrid solutions.
Plus, they're self contained and protected and have built in CYA. Not that it's all that hard to do this stuff safely, but off the shelf has a certain peace of mind.
LiFePo4 ones are meant to last 2000 cycles. They can charge via USB-C as well as from solar, and they have inverters as well.
Obviously, anything lithium isn't environmentally perfect, but I would imagine it will all be recyclable eventually, if it fails before then, just keep it and wait, it's small.
There's a bit of environmental issue with the non-replacable built in battery, though, but one could probably get around that with some hacking if they really want to replace it.
Portable folding solar panels are also insanely cheap for what they offer, sometimes they're less that $1/W, and they often have USB-C output to direct charge devices, in addition to 2.1mm.
Lithium does not like to be charged below freezing, which is another advantage for having everything compact and portable so you can bring it in.
I think that if I were going to build a fixed and permanently installed small solar setup, I would just want a panel with an outlet inside for a solar generator.
I'd add a switch, fuses, a reverse blocking diode, and a decent quick connector of some sort.
I might also add a voltage meter, and perhaps a USB charger, or even cigarette lighter outlet(with a 2 or 3A fuse, at most, definitely wouldn't trust a cigarette plug with 10A)
Most likely, I'd use Anderson PowerPoles for the main output, they seem to have a semi-standard for solar power (https://oh8stn.org/blog/2020/07/11/when-standards-get-in-the...)
Then, I would make a pigtail (With it's own inline fuse, in case the panel ever gets swapped with a much bigger one!) going from Anderson to 2.1mm, and plug that into the off the shelf solar generator.
I'd probably make a shelf for it, and position stuff such that the cable wouldn't easily bump into some rusty bucket of screws and short out.
In all the research I've done, aside from using batteries with built-in heating, I've never seen any easy way to recharge lithium in very cold temperatures.
The closest I've seen to a solution would be insulating the battery, and using two temperature switches, one to cut charging below zero, and one to turn on heating to warm it above zero using the solar energy. No idea how practical that would be, though.
Or, just using ultra capacitors, as I'll probably do if I get around to building a Meshtastic solar repeater.
